Re: [PATCH] riscv: fgraph: Fix stack layout to match __arch_ftrace_regs argument of ftrace_return_to_handler

[Pu Lehui]

On 2025/3/16 9:16, kernel test robot wrote:
> Hi Pu,
>
> kernel test robot noticed the following build errors:
>
> [auto build test ERROR on linus/master]
> [also build test ERROR on v6.14-rc6 next-20250314]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
>
> url:    https://github.com/intel-lab-lkp/linux/commits/Pu-Lehui/riscv-fgraph-Fix-stack-layout-to-match-__arch_ftrace_regs-argument-of-ftrace_return_to_handler/20250311-212440
> base:   linus/master
> patch link:    https://lore.kernel.org/r/20250311132243.2178271-1-pulehui%40huaweicloud.com
> patch subject: [PATCH] riscv: fgraph: Fix stack layout to match __arch_ftrace_regs argument of ftrace_return_to_handler
> config: riscv-randconfig-001-20250316 (https://download.01.org/0day-ci/archive/20250316/202503160820.dvqMpH0g-lkp@xxxxxxxxx/config)
> compiler: clang version 21.0.0git (https://github.com/llvm/llvm-project 87916f8c32ebd8e284091db9b70339df57fd1e90)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250316/202503160820.dvqMpH0g-lkp@xxxxxxxxx/reproduce)
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@xxxxxxxxx>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202503160820.dvqMpH0g-lkp@xxxxxxxxx/
>
> All errors (new ones prefixed by >>):
>
> > > <instantiation>:1:14: error: operand must be a symbol with %lo/%pcrel_lo/%tprel_lo modifier or an integer in the range [-2048, 2047]
>     addi sp, sp, -FREGS_SIZE_ON_STACK
>                  ^
>     arch/riscv/kernel/mcount.S:73:2: note: while in macro instantiation
>      SAVE_RET_ABI_STATE
>      ^
> > > <instantiation>:2:17: error: unexpected token
>      sw ra, FREGS_RA(sp)
>                     ^
>     arch/riscv/kernel/mcount.S:73:2: note: while in macro instantiation
>      SAVE_RET_ABI_STATE
>      ^
>     <instantiation>:3:17: error: unexpected token
>      sw s0, FREGS_S0(sp)
>                     ^
>     arch/riscv/kernel/mcount.S:73:2: note: while in macro instantiation
>      SAVE_RET_ABI_STATE
>      ^
>     <instantiation>:4:17: error: unexpected token
>      sw a0, FREGS_A0(sp)
>                     ^
>     arch/riscv/kernel/mcount.S:73:2: note: while in macro instantiation
>      SAVE_RET_ABI_STATE
>      ^
>     <instantiation>:5:17: error: unexpected token
>      sw a1, FREGS_A1(sp)
>                     ^
>     arch/riscv/kernel/mcount.S:73:2: note: while in macro instantiation
>      SAVE_RET_ABI_STATE
>      ^
>     <instantiation>:6:15: error: operand must be a symbol with %lo/%pcrel_lo/%tprel_lo modifier or an integer in the range [-2048, 2047]
>      addi s0, sp, FREGS_SIZE_ON_STACK
>                   ^
>     arch/riscv/kernel/mcount.S:73:2: note: while in macro instantiation
>      SAVE_RET_ABI_STATE
>      ^
>     <instantiation>:1:16: error: unexpected token
>     lw ra, FREGS_RA(sp)
>                    ^
>     arch/riscv/kernel/mcount.S:77:2: note: while in macro instantiation
>      RESTORE_RET_ABI_STATE
>      ^
> > > <instantiation>:2:17: error: unexpected token
>      lw s0, FREGS_S0(sp)
>                     ^
>     arch/riscv/kernel/mcount.S:77:2: note: while in macro instantiation
>      RESTORE_RET_ABI_STATE
>      ^
>     <instantiation>:3:17: error: unexpected token
>      lw a0, FREGS_A0(sp)
>                     ^
>     arch/riscv/kernel/mcount.S:77:2: note: while in macro instantiation
>      RESTORE_RET_ABI_STATE
>      ^
>     <instantiation>:4:17: error: unexpected token
>      lw a1, FREGS_A1(sp)
>                     ^
>     arch/riscv/kernel/mcount.S:77:2: note: while in macro instantiation
>      RESTORE_RET_ABI_STATE
>      ^
>     <instantiation>:5:15: error: operand must be a symbol with %lo/%pcrel_lo/%tprel_lo modifier or an integer in the range [-2048, 2047]
>      addi sp, sp, FREGS_SIZE_ON_STACK
>                   ^
>     arch/riscv/kernel/mcount.S:77:2: note: while in macro instantiation
>      RESTORE_RET_ABI_STATE
>      ^

Nice catch. The reason is that HAVE_DYNAMIC_FTRACE can be diabled when 
CONFIG_MMU=n, and lead to disable HAVE_DYNAMIC_FTRACE_WITH_ARGS. 
However, the current fgraph on riscv relies on the infrastructure of 
DYNAMIC_FTRACE_WITH_ARGS. So let's select HAVE_FUNCTION_GRAPH_TRACER 
depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS. I will send new soon.